Hypertension is a common disease that is characterized by persistenly elevated blood pressure (BP)1. BP increases with age and therefore is very common in the elderly. Patients with high BP are at a higher risk for cardiovascular disease, stroke, and kidney disease. Hypertension is known as a silent killer, because patients are often asymptomatic. Only when patients have severe high BP or hypertensive crisis, do they experience symptoms, such as throbbing headache, fatigue, nausea, vomiting, and/or chest pain.
Over 90% of people with BP have primary hypertension (essential hypertension). A number of mechanisms have been identified to be associated with primary hypertension, including environmental factors (i.e. lifestyle, overweight, excessive salt intake) and genetic factors. Fewer than 10% of patients have secondary hypertension, in which, either a comorbid disease (i.e. chronic kidney disease) or a drug is responsible for increasing BP (i.e. Pseudoephedrine, NSAIDs, systemic steroid, and more). The renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system (SNS) involve in the hypertension mechanism (see figure 1 below for hypertension mechanism that involves both RAAS and SNS).
Image reference: Y. Thieu 2017
RAAS = renin-angiotensin-aldosterone system; SNS = sympathetic nervous system; ACEis = angiotensin converting enzyme inhibitors; ARBs = angiotensin II receptor blockes; DHP CCBs = dihydropyridine calcium channel blockers; Non-DHP CCBs = non-dihydropyridine calcium channel blockers; SVR = systemic vascular resistance
Antihypertensive agents' sites of actions are numbered 1 though 8. Numbers 1 through 6 are the primary sites of action for major antihypertensive drugs, including (1) ACE inhibitors, (2) ARBs, (3) beta blockers, (4) CCBs, (5) thiazide diuretics, and (6) aldosterone antagonists.
Blood pressure (BP) = cardiac output (CO) x total peripheral resistant (TPR)
Cardiac output (CO) = blood (stroke) volume x heart rate (HR)
Blood pressure (BP) is determined by cardiac output (CO) times total peripheral resistance (TPR). While CO is the major determinant of systolic blood pressure (SBP), TPR is the major determinant of diastolic blood pressure (DBP). The table below shows activities that may lead to an increase in BP:
Table 1Determinants of High Blood Pressure1 |Favorite Table|Download (.pdf) Table 1 Determinants of High Blood Pressure1
|BP = CO x TPR |
|Overstimulation of RAAS ||↑ TPR, ↑ CO |
|Overactivity of the sympathetic nervous system ||↑ TPR, ↑ CO |
|Hyperinsulinemia ||↑ TPR |
|Excess sodium leads to ↑ fluid volume & ↑ cardiac preload ||↑ CO |
The overall goal of treating hypertension is to reduce associated morbidity and mortality from cardiovascular diseases (i.e. heart failure, kidney disease, acute coronary syndrome, etc.)1,2,3,4. Selection of specific antihypertensive pharmacotherapy should be based on ...